How Beta Sitosterol Works

Prostate Specific: In the human body, supplemental beta-sitosterol acts in several ways. First, it protects the prostate against growth caused by age-related reactivation of increased conversion of testosterone to the dihydrotestosterone (DHT) form. The higher production of DHT is normal from puberty to the early 20s, a man's most sexually active period. In an adult, however, reactivated production of DHT is a major contributing factor in undesirable growth of the prostate, or benign prostatic hyperplasia (BPH). By normalizing this conversion and depriving the prostate of the active metabolite DHT, prostatic tissue growth ceases and existing tissue atrophies. (Kirby RS, Christmas TJ. Benign Prostate Hyperplasia. London, England: Mosby-Year Book Europe Limited; 1993) Beta-sitosterol has been shown to do just this, naturally block this unwanted conversion, reducing and normalizing the supply of DHT to the prostate, and, in effect, maintain a normal male hormone balance for a healthy prostate. (Shrinkage in volume of the prostate from either beta-sitosterol or use of the herbal products appears to be a mixed clinical picture. Some reports indicate significant symptom improvement with no change in volume, while others report shrinkage. Since beta-sitosterol does not appear to affect prostate cell apoptosis of the cells stimulated by DHT [unlike cancer cells], the existing cells, and consequent volume increase will only reduce upon their death after their extended life span. The differences in reports may be due to the end period of the research protocols, since it seems that this could take as long as 18 months, long past the end point of most research. Also, beta-sitosterol has no demonstrated effect on inflammation of the prostate, which could account for some of the reported volume increase. For inflammation related products, see BCN's Epilobium and CM+ Cetyl Myristoleate.)

Effects on Prostate and other Cancer Cells: A second action specific to the prostate was shown for beta-sitosterol by Zahradnit, et al, in Fortschritte Med., vol. 98, p. 69-72 (1980). Here it was shown that beta-sitosterol inhibited the development of prostate adenoma (tumor) and depressed prostaglandins that are known to support tumor growth. A similar action has been demonstrated in mice for colon cancer, with beta-sitosterol inhibiting the growth of malignant tumors from chemically-induced colon cancer. In a more recent study, beta-sitosterol was shown to inhibit HT-29 human colon cancer cell growth. The clinical implications of this are yet to be researched.

In Vitro Effects on Prostate Cancer Cells: The following article is suggestive of one of the possible mechanisms of beta-sitosterol.

Epidemiological evidence has shown that men consuming a low-fat, high-fiber diet containing high amounts of plant products have a lower risk of prostate cancer than men consuming a Western diet. One of the main differences between these two diets is the type of dietary fat, including dietary sterols. This study was undertaken to compare the effect of two dietary sterols on prostate cancer cells in vitro. Beta-Sitosterol (SIT), the most common plant sterol, and cholesterol, an animal sterol, were compared for effect on LNCaP cell growth, differentiation, apoptosis, and sphingomyelin cycle intermediates. Cells were treated for up to seven days with sterols delivered by a cyclodextrin vehicle. Compared with cholesterol, SIT (16 microM) decreased growth by 24% and induced apoptosis fourfold, which was accompanied by cell rounding and a 50% increase in ceramide production. No effect was observed on differentiation as measured by prostate-specific antigen and prostatic acid phosphatase, although total acid phosphatase increased with SIT treatment for up to seven days. The results suggest that the decrease in cell number and increase in apoptosis associated with SIT treatment are mediated by activating the sphingomyelin cycle.

Effects in Human Studies for BPH:
Two studies have shown beta-sitosterol to be "an effective option in the treatment of BPH." The abstracts from these two articles are reprinted here for your review:

Abstract: Medical treatments have become available for benign hypertrophy of the prostate, including alpha-receptor blocking agents and 5-alpha-reductase inhibitors. Drugs derived from plants, for which no precise mechanism of action has been described, are widely used for this purpose in Europe. In a randomized, double-blind, placebo-controlled multicentre study, 200 patients (recruited between April and October 1993) with symptomatic benign prostatic hyperplasia were treated with either 20 mg beta-sitosterol (which contains a mixture of phytosterols) three times per day or placebo. Primary end-point was a difference of modified Boyarsky score between treatment groups after 6 months; secondary end-points were changes in International Prostate Symptom Score (IPSS), urine flow, and prostate volume. Modified Boyarsky score decreased significantly with a mean of -6.7 (SD 4.0) points in the beta-sitosterol-treated group versus -2.1 (3.2) points in the placebo group p < 0.01. There was a decrease in IPSS (-7.4 [3.8] points in the beta-sitosterol-treated group vs -2.1 [3.8] points in the placebo group) and changes in urine flow parameters: beta-sitosterol treatment resulted in increasing peak flow (15.2 [5.7] mL/s from 9.9 [2.5] mL/s), and decrease of mean residual urinary volume (30.4 [39.9] mL from 65.8 [20.8] mL). These parameters did not change in the placebo group (p < 0.01). No
relevant reduction of prostatic volume was observed in either group. Significant improvement in symptoms and urinary flow parameters show the effectiveness of beta-sitosterol in the treatment of benign prostatic hyperplasia.

Abstract: OBJECTIVE: To report the results of a double-blind, placebo-controlled trial to evaluate Azuprostat, a beta-sitosterol, in patients with symptoms of outlet obstruction caused by benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: A randomized, double-blind and placebo-controlled clinical trial was conducted to assess the efficacy and safety of 130 mg free beta-sitosterol (phytosterol) daily, using the international prostate symptom score (IPSS) as the primary outcome variable. In total, 177 patients with BPH were recruited for 6 months of treatment in 13 study centres. In addition to the relative difference in the IPSS, changes in quality of life, peak urinary flow rate (Qmax) and post-void residual urinary volume (PVR) were recorded. The drug used in the trial consisted of a chemically defined extract of phytosterols, derived for example from species of Pinus, Picea or Hypoxis, with beta-sitosterol as the main component. RESULTS: There were significant (P < 0.01) improvements over placebo in those treated with beta-sitosterol; the mean difference in the IPSS between placebo and beta-sitosterol, adjusted for the initial values, was 5.4 and in the quality-of-life index was 0.9. There were also significant improvements in the secondary outcome variables, with an increase in Qmax (4.5 mL/s) and decrease in PVR (33.5 mL) in favour of beta-sitosterol when adjusted for the changes after placebo. CONCLUSION: These results show that beta-sitosterol is an effective option in the treatment of BPH.

Effects on Cholesterol:
For over 30 years, research has been conducted on the use of beta-sitosterol and its effects on both cholesterol and triglyceride levels. Dietary supplementation has been shown to effect both the absorption of dietary cholesterol, and the systemic levels of cholesterol and triglycerides, helping to normalize both. Beta-sitosterol is known to interfere with the absorption of cholesterol, possibly because of its competition for the enzyme cholesterol esterase. Systemically, 300 mg per day of beta-sitosterol has been shown to lower blood serum cholesterol and triglyceride levels, if the levels are above normal. It can also improve the HDL / LDL ratio.

Other relevant effects:
Beta-sitosterol has been shown to have anti-inflammatory and antipyretic properties.

Safety:
There are no known safety issues or side effects with the use of beta-sitosterol. There are no known interactions with prescription drugs or any known drug interactions with current conventional cancer therapies.

It is commonly recommended that zinc intake should not exceed 50 mg. per day without supervision of a qualified health professional, for any extended length of time